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Topic: Citsuma Prague (Read 5246 times)

Yes I already thought that. It eliminates the L1 if I remember well.To root cuttings must not be difficult. I shall do it.What seems harder is to recreate a plant starting from roots only...I have seen it many times append naturally but never did it in purpose.

If I am right we might obtain a copy PMP or a very near form MMP (without thorns!).The MMP could be less cold hardy than PMP.I don't know from which layer the new L1 is created...

Original L1 will be lost in root cuttings, in most cases it will be replaced by cells from L3, but it could also come from former L2, so MMP at least theoretically is possible. Since Prague is occasionally giving pure poncirus shoots, it is not entirely stabilized periclinal chimera, probably L2 does contain some proportion of poncirus cells.

Hi,i'm an invidicual breeder interested by chimera, so i've came across the Cistuma Prague. Hope i can get a plant this fall and start playing with it. I'm new to citrus as i want only trees that could be planted on my property (-15°C min), so Prague seems to be able to make the deal

My hypothesis is that Prague is a SSP chimera (L1/L2 satsuma and L3 poncirus).

L3 : Rose/Blackberry thorns are from L1 but this is a different kind of thorns. "Studying" different chimeras between medlar and hawthorn, i came to the conclusion that spines are from L3. To test this hypothesis, one could root Prague, and make a root cutting to root. The plant should be all L3 and thus should be poncirus.

L2 : Seeds are from F2. As Prague seems to carry few seeds, it would lead to S2 = satsuma. Seedlings should be pure sastuma. Also L2 + L3 gives leaf form, so if both L2 and L3 where poncirus, i guess leaves would be trifoliate.

L1 : Fruit juice is L1, so from taste it is Satsuma

To my knowledge there is no way to try to mix layers of the chimera to try to get new layer associations

To test this hypothesis, one could root Prague, and make a root cutting to root. The plant should be all L3 and thus should be poncirus.

As i wrote above, in most of the cases in root cuttings L1 will be replaced by L3 cells that are very invasive, but it could be also be formed by the cells from the former L2 that are present in the roots.

L2 : Seeds are from F2. As Prague seems to carry few seeds, it would lead to S2 = satsuma. Seedlings should be pure sastuma. Also L2 + L3 gives leaf form, so if both L2 and L3 where poncirus, i guess leaves would be trifoliate.

Sylvain demonstrated that fruits and seedlings are pure satsumaLeaves are formed by all three layers, with L1 forming a leaf margin, this explains the fact that Prague have a very particular foliage.

In "The citrus industry" I found few lines going in that way, but it's old (1968):

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In Japan, two citrus forms considered to be synthetic periclinal chimeras have been in existence for some fifty years (Samura and Nakahara, 1928; Takahashi, 1962). The Kobayashi Mikan is recorded as having arisen at the junction where a satsuma scion was grafted onto Natsudaidai. This scion was accidently [sic] broken off at its base, after which two adventitious buds emerged, one of which grew into the original chimeral tree. This chimera produces fruit with rind like Natsudaidai, but with flesh like satsuma. It is seedy, and seedlings from one fruit were reported to be Natsudaidai (Dr. Yuishiro Tanaka, unpublished). In this chimera, histogenic Layer II appears to be genetically Natsudaidai, while Layer I should be satsuma.

and

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It appears that a mutant color factor is present in the Thompson in histogenic Layer I; this layer provides at least part of the cells of the juice vesicles

If it is confirmed we could be in presence of MMP as you say.

It means that among the roots adventices we might find many PMP and few MMP. Just the same as if the origin is PMP, because the L1 is dropped off.In the first hypothesis (PMP) the majority should be identical to the origin and in the second hypothesis (MMP) the majority should be different from the origin.

The suspense is unbearable!...

And indeed if the truth is "It seems that the shoots are made of L2 or L3." we shall obtain many poncirus and few mandarines...

In the citrus fruit, the first germ layer L1 producesthe juice sacs of the fruit and the epidermis of thepericarp, while L2 produces seeds, segment walls, thehypoderm and the mesocarp of the pericarp, and L3the vascular bundles (Cameron et al., 1964; Fost &Krug, 1942; Kuhara, 1988).

It means that among the roots adventices we might find many PMP and few MMP. Just the same as if the origin is PMP, because the L1 is dropped off.In the first hypothesis (PMP) the majority should be identical to the origin and in the second hypothesis (MMP) the majority should be different from the origin.

I dont understand your phrase. Root tissue is pure L3 in trees (unlike in some rhizomes and some other cases) so any root adventices should be pure poncirus.

For L1 = juice i'm not so sure.It seems that L1 is juice sac. I think juice is mostly L1 but can be somewhat modified by other layers (like sugar and acidity level, quoted in the paper). Maybe L2 = satsuma is important to be as close as possible to satsuma flavor. But color of rind and juice is L1, so i guess it is sure that L1 is satsuma (i let you confirm, as i'm a complete beginner with citsuma, satsuma and poncirus).

I guess that when you say F2 and F3 it means L2 and L3. Unfortunatly tree roots are pure L3. Other layers are present when roots are not true root but modified organs (blackberry, potatoes, mint...)

It is important to note that we do not have the original Citsuma , but only grafted plants.The rooted stem cuttings could produce roots either directly from cambium cells (L3) or from callus that potentially could involve cells from any layer.

It is important to note that we do not have the original Citsuma , but only grafted plants.The rooted stem cuttings could produce roots either directly from cambium cells (L3) or from callus that potentially could involve cells from any layer.

What i've understood is that root tissue is L3, not that it comes from cambium (L3).

„Hybrid (Unshiu x P. ITSZ Prague“ is the greatest mystery among citruses for me.Is it a hybrid? Is that a chimera? Or maybe something else? Any mysterious play of nature? I do not know.Many of the previously published information I have discovered. Here I will try to summarize the most important thing about this cultivar I know.

1981: I started growing citrus

1987: The first literary reference to the hybrid. "Citrus Growing", c. SZN 1987, Ing. Stanislav Husak, CSc., Doc.Ing. Vladimír Táborský, CSc., Prof. Ing. Pavel Valíček, DrSc., Page 21 - 2.2. Fundamentals of genetics and citrus breeding. Photo 45: "Hybrid (Unshiu X Poncirus trifoliata) bred on ITSZ Praha".It must be said that this was the first and at the same time the last mention of this hybrid in literature in the Czech Republic.Note: : Prague is the capital of the Czech Republic. ITSZ is a university. Her name is the institute of tropical and sub-tropical agriculture.Previously, many books on citrus growing have been published in the Czech Republic. Until 1993, a magazine on citrus growing was published- 5 times a year. The Citrus Growers' Association had 10,000 members (the population of the Czech Republic is 10,000,000 people !!!). In a country where citrus trees can not normally be grown !!Why it was not published anywhere else is a mystery to me.

1989-1996: I have seen hybrids several times but Cold Hardy citruses were outside my area of interest. I also met with many interesting hybrids, mostly from the former USSR.I've heard it repeatedly : Badly growing. It does not produce. If you want the weeds in the greenhouse, grab a bud.

2004: Mr. Zdeněk Černoch began to make his collection of citruses, which now belongs to one of the largest in Central Europe. Especially cold hardy citruses. Aroused great interest in them in the Czech Republic.

2007:I was also interested for cold hardy citrus. The source of grafts was mainly Broža Petr and Zdeněk Černoch. The Bud from which my plants originated was taken by Peter Broža. From its small 15cm large plants growing in the middle greenhouse.

2009/2010:Plants at Petr Broža and Zdeněk Černoch died in the winter. They have recovered from me. All plants sold by Zdeněk Černoch all over Europe from 2010 until 2014(?) they're out of my buds. Sometimes later, Zdeněk Černoch brought the other buds from France. I do not know from whom.

2016:I managed to contact Prof. Ing. Pavel Valíček, DrSc., Author of the book from 1986.He told me that the hybrid was bred prof. Pospíšil. Classical crossbreeding and subsequent selection. Sometime between 1971 and 1977.

Prof. Pospisil is unfortunately dead.

My friend in Prague visited Mrs. Rozinková, who was a collaborator of prof. Pospíšil. She's an older lady, no new information more. She just confirmed the information from Mr. Valíček. The new information was just that there were also experiments with seed irradiation and any others

From information from Petr Broža I know that B. Voss was wearing some citrus from ITSZ greenhouses in Prague. Whole plant with roots. It was supposed to be the hybrid Uhshiu X P.T. ITSZ Praha. It is certain that many other similar hybrids originating in the former USSR were in the ITSZ greenhouses at that time.

Information from Mr. Hlaváč (Head of ITSZ Greenhouses in Prague) - He confirmed that B. Voss took some citrus plant from the greenhouse. It was not a hybrid but something else. The original plant is still growing in the greenhouse of ITSZ Praha. If I want to, I can come and see.Meanwhile, I did not have time for this (greenhouses are not publicly accessible, the visit needs to be arranged in advance).

In 2016, I accidentally managed to provide at MU Brno (Masaryk University, the Faculty of Natural Science) a cytometric analysis of the genome size of the hybrid. Incl. comparison of genome size Unshiu and P.T and F.D.The analysis was repeated three times using different parts of the hybrid tissue. For all samples, only one peak was found in the histogram. This means that the plant has only one genome, ie. the plant is of hybrid origin. The chimera should have two peaks in the histogram because it carries two different genomes. Separately tested parents of the hybrid have the genome size significantly different, the histogram would be clearly visible.However, cytometric analysis of the genome size can not be, for many reasons, a 100% result.---------------------------------------------

For different growers, the hybrid is completely different.

The Sylivian plant grows almost up. My plant a willow. Without counting the height of rootstock, they are approximately the same size. I have to constantly shape the plant. Otherwise, it would look like the second and third my plant that crawls 40cm above the ground.

My and other known breeding plants are free of seeds. Sylvian seed produces.

For me, Bi- and Tri-foliate leaves fall in autumn only in older plants, not in young ones.

Sylvian plant blooms in spring twice, my only once.

My plants show mild symptoms of psoriasis or leprosy. But psorosis or leprosy is definitely not.

At Sylvian seedlings produce non-trifoliated plants. I wanted to verify this very much. Except for natural pollination, all the flowers were artificially pollinated. No seeds. Not a germ.

In experiments done in MU Brno one symmetrical peak of genome size was observed, but they have not performed a crucial control demonstrating that an artificial mixture of nuclei from poncirus and unshiu gives two distinct genome sizes.

It's not as likely, but one possibility is it could be a triploid, if one of the gametes was unreduced. (This can occasionally happen by natural processes) That could potentially have left the entire genome of one of the parents intact. (In that case it would be 2/3 poncirus and 1/3 mandarin, or 1/3 poncirus and 2/3 mandarin)Being a triploid would also explain lack of seeds or low seed count.

(for those of you who may not understand, occasionally during production of the plant's reproductive cells meoisis fails to take place, and then the reproductive cell has the full set of two chromosomes, so when it later combines with another reproductive cell the resulting zygote will then have three sets of chromosomes, instead of the usual two that most citrus plants have)

In experiments done in MU Brno one symmetrical peak of genome size was observed, but they have not performed a crucial control demonstrating that an artificial mixture of nuclei from poncirus and unshiu gives two distinct genome sizes.

That's true, I agree.Purely mathematical: Under certain circumstances, only one peak can be found at the chimera. At the same time it has to be said that the peaks can be really two. It depends only on how the initial curves of the separate elements are steep.The problem is that I do not have histograms. From histograms, this could be further investigated. The Results was communicated to me only by phone and I received one short e-mail.

I'm not a botanist. I do not know how genomic size histograms appear in plants on a flow cytometer. However, if I had to estimate, I would think that the proportion of genomes of different size (5%) would be very close to 0% of the representation. If this reasoning is correct, there must always be two peaks on the histogram. For a chimera and a mixture of separate components.

Snek,I have the same problem with theguy from Brno, his first reply was very complete and helpful, but he has not replied to my further questions. I am not a botanists either, but in my previous life ( I am retired now) I was working in Molecular Biology and Human Genetics and know perfectly the method that was used by them. It is not the best way to resolve the chimerism, the simplest one is just to use one or two plastid DNA marker that distinguish poncirus and unshiu.

Ilya,the same was with me. First was very complete and helpful, but later he has not responded. I just gave the samples, I took them to the university lab, I defined what I want to know. I had doubts, and so it was repeated again.

I received the results by e-mail. Three short sentences.I asked for details. Without an answer. After many urgings, I learned that he thought your colleague had already sent me or yes, yes, I'll send. I just received a list of what was tested for the first time and the second time. I do not have anything to do with the third repeat tests. Just one sentence in an email.

The list that I received is also an artificial mixture of "C. unshiu 'Planellina + ITSZ doublelist". Logically I assume that if there was only one peak in the histogram, I would have been told that the analysis was not conclusive. But I was told that the data obtained eliminated chimerism. This should mean that there were two peaks in this sample. If this is not a big mistake. Direct ignorance. It is possible, but I do not want to believe it.

Last news. In the crop of this year most of the fruits are flatten at the distal end, like satsumas. The fruits of previous years were near-spherical. I find from 0 to 3 seeds per fruit. The seeds are also different. They are big and we can see trough the thin testa the green cotyledons. They look poly embryonic.The pulpe is still the same: a pure mandarine.